HP XP Racks - Manual (Page 30)

Figure 5 (page 30) provides an overview of copy group containers. It depicts an operation
performed on the copy group container (copy group ID: CG.UR), and shows how the operations
are performed in batch for the consistency groups with the consistency group IDs 71 and 72.
Figure 5 Copy group container overview
Extended consistency groups
In a 4x4 or 4x4x4 configuration, consistency can be preserved among Continuous Access Journal
Z consistency groups spread across multiple storage systems. A copy group container that can
preserve consistency between multiple Continuous Access Journal Z consistency groups is called
an extended consistency group (EXCTG).
When an extended consistency group ID (EXCTG ID) is specified in the copy group container, the
container is registered in the storage system as an EXCTG, and consistency between the consistency
groups in that copy group container is preserved.
Specifying an EXCTG ID in a copy group container is explained in “Defining an EXCTG” (page 653) .
The process of preserving consistency in an extended consistency group is called arbitration
processing. A storage system that executes arbitration processing is called a supervisor DKC, and
remote storage systems other than the supervisor DKC are called subordinate DKCs.
Figure 6 (page 31) provides an overview of arbitration processing in an extended consistency
group.
30 Overview of HP XP7 for Business Continuity Manager